diff --git a/includes/locale.inc b/includes/locale.inc
index c168da0..5af2cc3 100644
--- a/includes/locale.inc
+++ b/includes/locale.inc
@@ -457,6 +457,10 @@ function locale_language_url_rewrite_url(&$path, &$options) {
               $options['base_url'] = str_replace('https://', 'http://', $options['base_url']);
             }
           }
+
+          // Add Drupal's subfolder from the base_path if there is one.
+          $options['base_url'] .= rtrim(base_path(), '/');
+
         }
         break;
 
diff --git a/modules/locale/locale.test b/modules/locale/locale.test
index 9ffec9f..145c790 100644
--- a/modules/locale/locale.test
+++ b/modules/locale/locale.test
@@ -2514,7 +2514,7 @@ class LocaleUILanguageNegotiationTest extends DrupalWebTestCase {
 
     foreach (array('it', 'fr') as $langcode) {
       // Build the link we're going to test based on the clean URL setting.
-      $link = (!empty($GLOBALS['conf']['clean_url'])) ? $langcode . '.example.com/admin' : $langcode . '.example.com/?q=admin';
+      $link = (!empty($GLOBALS['conf']['clean_url'])) ? $langcode . '.example.com' . rtrim(base_path(), '/') . '/admin' : $langcode . '.example.com/?q=admin';
 
       // Test URL in another language.
       // Base path gives problems on the testbot, so $correct_link is hard-coded.